Method and apparatus for simultaneously applying to an extended cylindrical object a coating and a plastic film wrapping to retain the coating

ABSTRACT

This invention describes a method of placing a coating of material circumferentially about an extended cylindrical object and holding the material in place by means of a longitudinally folded and sealed plastic film about the long object. The diameter of the resulting plastic cylinder is greater than that of the object, so as to provide sufficient space in the annulus for the coating material. The two edges of the plastic are sealed either by cementing one to the other or by applying a sealing strip over the edges. The coating material is applied into the annulus through a pipe between the object and the film cylinder. By the use of a heat shrinkable plastic film the film can be shrunk to tightly fit the coating material.

, 1974 c. F. STRAUGHAN ETAL 3,832,260

METHOD AND APPARATUS FOR SIMULTANEOUSLY APPLYING TO AN EXTENDEDCYLINDRICAL OBJECT A COATING AND A PLASTIC FILM WRAPPING TO RETAIN THECOATING Aug. 27

5 Sheets-Sheet 1 Filed may 17, 1972 Aug. 27, 1974 c, STRAUGHAN ETAL3,832,260

METHOD AND APPARATus FOR SIIUL'IANEOUSLY APPLYING TO AN EXTENDEDCYLINDRICAL OBJECT A COATING AND A PLASTIC FILM WRAPPING TO RETAIN THECOATING 5 Sheets-Shut a Q3) Wm v w QNQ mwg $9 A 27, 1914 F. STRAUGHANm1. 3,832,260

METHOD AND APPARATUS FOR SIIULI'ANEOUSLY APPLYING TO AN EXTENDEDCYLINDRICAL OBJECT A COATING AND A PLASTIC FILM WRAPPING T0 RETAIN THECOATING Filen May 17. 1972 5 Sheets-Shoot Aug. 27, 1974 c, STRAUGHANETAL 3,832,260

um'raon AND APPARATUS FOR SIMULTANEOUSLY APPLYING TO AN EXTENDEDCYLINDRICAL OBJECT A comma AND A PLASTIC FILM WRAPPING TO RETAIN THEcomma Filed lay 17, 1972 5 Sheets-Shoat c All. 27, 1974 c, STRAUGHANETAL 3,832,260

METHOD AND APPARATUS FOR sIuuLTAnEousLY APPLYING TO AN EXTENDEDcYLINDRIcAL OBJECT A COATING AND A PLASTIC FILII WRAPPING To RETAIN THECOATING Filed May 17, 1972 5 Sheets-Shoot 5 United States Patent Oflice3,832,260 Patented Aug. 27, 1974 Int. Cl. 1529f 1/10 US. Cl. 156-390 19Claims ABSTRACT OF THE DISCLOSURE This invention describes a method ofplacing a coating of material circumferentially about an extendedcylindrical object and holding the material in place by means of alongitudinally folded and sealed plastic coating. This is accomplishedby folding and wrapping a plastic film about the long object. Thediameter of the resulting plastic cylinder is greater than that of theobject, so as to provide suificient space in the annulus for the coatingmaterial. The two edges of the plastic are sealed either by cementingone to the other or by applying a sealing strip over the edges. Thecoating material is applied into the annulus through a pipe between theobject and the film cylinder. By the use of a heat shrinkable plasticfilm the film can be shrunk to tightly fit the coating material.

CROSS REFERENCE TO RELATED APPLICATION This application is acontinuation-in-part of the copending application Ser. No. 142,452, ofthe same title, invented by one of the two coinventors of thisapplication and filed May 12, 1971.

BACKGROUND OF THE INVENTION This invention is in the field of pipecoatings and protective wrappings. More particularly it is concernedwith the application to long cylindrical objects such as tubes, pipes,electrical cables, etc., of uniformly thick circumferential coatings ofselected materials, and the protection of the coatings by means ofsealed longitudinal wrappings of films of plastic, paper, etc.

Still more particularly, this invention is concerned with thesimultaneous application of a continuous plastic or synthetic film orwrap to a cylindrical object, such as a pipe or conduit and theinjection of a circumferential coating of a selected material into theannular space between the object and the film.

Pipelines are typically coated with a helically wound wrap of chemicallytreated paper, felt or similar protective material. The wrap issometimes bonded to the pipe by an undercoating of adhesive, or similarmaterial, applied to the pipe by brush, spray or the like. This processis only workable when the pipe coating is very thin, is of the propernature, and is of the proper consistency. If thlClk coatings are appliedby this method, pressure of the wrappings tends to distort the thicknessand character of the coating, with unsatisfactory results.

Also there are many applications in industry, particularly in thepetroleum industry, where a thermal insulating coating, such as producedby means of a foamed plastic material, are required. One application isin the pipelining of heavy, viscous oil. Such oil can be heated to makeit of low enough viscosity to pump, and the heat conserved by means ofthe insulation so as to permit the transport of the viscous oil overlong distances. Also, there are delicate objects such as a telephonecable, containing many wires and coaxial conductors, that may be damagedvery easily by side pressure on the cable. It is customary, therefore,to place these cables in rigid conduits so as to free the cable of anyside pressure which might damage it. However, by the use of deformableprotective coatings, such as the foamed plastic, these delicatelongitudinal objects, such as telephone cables, can be protected againstthe pressure of rocks and other objects in a trench.

SUMMARY OF THE INVENTION It is a principal object of this invention toprovide a method and apparatus for simultaneously applying a uniformlythick coating of a selected material to a pipe, conduit, cable or otherlong cylindrical object and simultaneously forming, wrapping and sealinga circumferential layer of plastic film, to contain and protect theapplied coating.

It is a further object to accomplish this with a pipeline travelingdevice or apparatus, through which the pipe or conduit will travel.

It is a further object to provide a coating of foam plastic material inthe annular space between the long cylindrical object and thecircumferential plastic film.

These objects are realized and the limitations of the prior art devicesare overcome in this invention by providing an assembly which can guidea long cylindrical object therethrough, or can be transported along suchan object, such as a pipeline. Means are provided on a frame forsupporting the long cylindrical object by rollers. The frame carries astrip of plastic film which is folded, formed and wrapped around thecylindrical object to form a longitudinal overlapping seam with theplastic film, forming a complete and void-free protective coating. Theforming device, also known as forming head or simply, former, is ofcylindrical form and of an internal diameter substantially the same asthe diameter of the resulting plastic cylinder, which is to form theouter surface of the finished coating.

The flat strip is formed around the former into the cylindrical form,and the edges are sealed by means of an overlapping strip of gummed tapewhich is pressed on the outside of the seam, and against a longitudinalpressure bar or mandrel supported on the inside of the plastic cylinder,so that the pressure of the roller will firmly attach and seal thecylinder. The edges of the formed cylinder can be sealed by any of theknown commercial methods such as by heat, adhesive, ultrasonic bonding,etc. The pressure bar is arcuate in shape to match the interior surfaceof the cylinder. It need not be much wider than the roller itself, andparticularly does not need to be a continuous cylindrical mandrel, suchas is described in the copending application Ser. No. 142,452. Thisapplication is a continuation-in-part and an improvement over thecopending application, in that it does not require the use of acontinuous cylindrical mandrel in the forming of the cylindrical plastictube. It also provides an improved type of forming means that is simplerto construct.

BRIEF DESCRIPTION OF THE DRAWINGS These and other objects and a betterunderstanding of the principles and details of the invention will beevident from the following description taken in conjunction with theappended drawings, in which:

FIG. 1 is a general view of the apparatus of this invention.

FIG. 2 is a plan view of the same apparatus taken at to the direction ofFIG. 1.

FIG. 3 is a cross section taken through FIG. 1 in the plane 3-3.

FIGS. 3A, 3B show enlarged view of part of FIG. 3.

FIG. 4 represents a templet for cutting out the two matching parts ofthe former.

FIG. 5 represents a bracket for holding and supporting the former.

FIG. 6 represents a view of the critical portion of this apparatus,namely, the forming head, the pressure bar for supporting the sealing,roller, and the pipe for injecting the coating material.

FIGS. 7A, 7B, 7C, 7D, 7E and 7F illustrate the various steps in theconstruction and assembly of the forming head of this invention.

FIG. 8 illustrates an alternate method of applying pressure to thesealing strip.

FIG. 9 illustrates an embodiment of this invention particularly adaptedfor shop mounting.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings,and in particular to, FIGS. 1, 2 and 3, which show various views of thegeneral assembly of one embodiment of this invention. The numeral 10indicates generally a frame which supports all of the apparatus and isadapted to be relatively longitudinally transported with respect to thelong cylindrical object.

While the long cylindrical object can be a rigid or flexible cylindricaldevice, such as a pipe, conduit, electrical cable or similar object, forconvenience it will be described in this application as a length of pipeof rigid metallic construction, such as a pipeline for transportingliquid materials, such as petroleum. In this case it is convenient tohave the coating apparatus of this invention travel along the pipe sothat the coating can be applied in one continuous operation, after whichthe pipe is dropped into its trench and covered. The frame 18 issupported by means of rollers 21, 22 and 23 so that it can be rolledalong the pipe. Drive means (not shown) but well known in the art) canbe used to drive the rollers 21, 22, 23, to cause the frame 18 to travelalong the pipe 20, or, conversely, to cause the pipe to be traversedthrough the frame. in some instances, particularly for mill operationsand for non-rigid objects, a roller 24 may be used to support the coatedpipe. In such cases the roller 24 is supplied with soft, compressiblecoating so as to give firm uniform support to the coating of the pipe.

The strip film material is indicated generally by the numeral 16. Theforming head which converts the strip into a cylindrical tube of film isindicated generally by the numeral 12. The sealing strip which coversand seals the overlapping edges of the film strip is indicated by thenumeral 14. A roll 26 of plastic, paper or other film 28, is supportedon a spindle 27 the axis of which is perpendicular to the axis of thepiperline 20. This film is of sufiicient width so that when it is formedinto a longitudinal cylinder it will provide a cylinder of the selecteddiameter and, if desired, an overlapping layer of one edge on top of theother. The seam can be bonded by overlapping and cementing the two edgestogether. The edges can also be abutted or overlapped and a separateplastic strip with gum cement on one surface can be applied to hold thetwo edges of the film in proper position. The two edges of the film canbe abutted with the separate sealing strip applied. Other known methodsof sealing can be used. It has been found convem'ent to use a certainamount of overlap of the two edges with the separate gummed strip forholding the two edges in their proper position.

The strip 28 of plastic film 26 goes by way of a plurality of rollers29, 30, 31, etc., and approaches the front end of the former 12 at anacute angle, which is normally in the range of This angle is notcritical and may vary over the range of 10 to- 40, and may even increaseto an angle greater than 90 with respect to the axis of the former.However, an acute angle is preferred.

The forming head 12 will be described in greater detail in connectionwith FIGS. 4, 5, 6, and 7. However, it is a cylindrical device 34 whichis supported to the frame 18 by means of bracket 36 and bolts 38. Theformed plastic strip emerges from the downstream end of the former as acylinder 35 of plastic film, with two overlapping edges 46 and 48. Thisis shown more clearly in FIG. 3A which is an enlarged portion of FIG. 3,which is a cross section of the assembly of FIG. 1 of the plane 33.

To hold the two edges of the cylindrically formed strip in place, a rollof thin (0.001") narrow strip of plastic material 50 is supported on atransverse bearing 51 and the strip unrolled from the reel 50 passesunder a pressure roller 54 which is preferably of deformable shape sothat it can deform to the contour of the outside of the edges of theplastic cylinder. It presses these edges together and against a supportor pressure bar 44 which is supported by means of a bracket 80. Bracketalso supports the pipe or conduit 42 through which is introduced thecoating material into the annulus between the pipe 20 and the plasticcylinder 35. The arcuate bar 44 and the pipe 42 are illustrated moreclearly in FIGS. 3 and 3A.

In the copending application Ser. No. 142,452, the supporting deviceagainst which the pressure roller 54 acted was a complete cylindricaltubular mandrel, about which the plastic was wrapped and sealed.However, it has been determined by experiment and by operatingexperience that only an arcuate segment of the cylinder, or an arcuatebar is required, and consequently the complete tubular mandrel has beenremoved, providing a simpler assembly. The pressure roller 54 is mountedon an arm 55 which is hinged at point 56 and spring pressure 57 isutilized to apply the desired force between the sealing strip 53 and theedges of the plastic cylinder 35.

FIG. 2 is a view of the apparatus of FIG. 1 looking down on top of thepipe and shown partly in cross section. The pipe 20 is shown in outline.The arcuate support bar 44 is supported by the bracket 80 in front ofthe pipe 20. A supply pipe 42 is provided for the foaming material,which comes from reservoir 40 and is applied close to the top edge ofthe pipe 20. The forming head, of which only part is shown as 34, formsthe strip 28 in a curved portion 32 and into a cylinder 35 of theplastic material. The portion including the overlapped edges is notshown in this figure since that is in front of the plane of the crosssection. The coating material is introduced through pipe or conduit 41into the annular space, where it foams to fill the annular space, and isshown as 60. While the pipe 42 is rigid inside the forming head (asshown in FIG. 6) the portion 42B that connects it with the supply tank40 will, in general, be flexible. Heating elements 66 may be used toheat the film to cause it to shrink, if it is a heat shrinkable plasticmaterial, so that the diameter of the cylinder 35' downstream of theheating elements is of smaller diameter than the cylinder 35 as it isformed by the forming head 34.

FIGS. 3 and 3A illustrate more clearly the nature of the arcuate supportbar 44, the coating supply pipe 42, the two overlapped edges 46 and 48of the plastic cylinder and the sealing strip 53. In general the use ofa foaming plastic coating material is very desirable. First of all, itprovides good thermal insulation as well as electrical insulation. It isdeformable so that it can conform to minor irregularities in the supportsurface of the trench into which the pipe or other project is placed. Itcan be designed so as to set up and harden very rapidly so that there isno serious problem in the supporting of the coated object shortly afterthe foam is injected into the annulus. Furthermore, the reaction offoaming is an exothermic reaction, and heat is given off, which raisesthe temperature of the foaming material and therefore heats the plasticfilm. If the film is heat shrinkable, it

will thereupon be drawn more tightly around the foam plastic to providea very tight, rigid film coating.

In FIG. 3B is shown a variation of FIG. 3A in which the arcuate bar 44has been removed. In this case the pipe 42 through which the foam isprovided also serves as the backup member against which the roller 54presses to seal the adhesive coated strip 53. The surface contour 54' ofthe roller 54 is curved to fit the contour of the pipe 42. The roller 54can also be of deformable elastomeric material to adjust to variationsin the surface 42, and thickness of material, etc.

The film as normally supplied is not weted by the plastic and after thecoating has been applied it is possible to strip off the plastic film,if desired. On the other hand it is possible by means of a commercialtreatment, called corona treatment, to prepare a modified surface of thefilm to which the foaming plastic adheres very strongly and binds theplastic and the film together to provide a stronger overall unit. Thiscorona treatment is a commercial process which is available on themarket and need not be described further. Of course, other materialsthan heat shrinkable plastic film can be used, such as paper or othersimilar sheet materials, to which the plastic can be made to adhere byvarious types of treatments well known in the art.

DESIGN AND CONSTRUCTION OF THE FORMING HEAD The heart of the system ofFIG. 1 is the forming head 12. This is a device which is designed sothat a flat, wide strip of sheet material can be brought, at an acuteangle to the axis of the former, and the material is bent over theentering edge or forming edge of the forming head so that the sheetmaterial will be in continuous sliding contact with the surface of theformer and will issue from the second end as a continuous cylinder withoverlapped or abutted edges which can be sealed to form a completecontinuous cylindrical tube. The contour of the entering edge is veryimportant, because if is is not, properly designed material will notflow smoothly but will stretch at one point or bunch up at anotherpoint, with the result that the output cylinder will not be a smoothcylindrical surface. It has been found by experience that thecylindrical portions of the former can be made from a sheet which is cutalong a line which represents a parabola, with its axis along thecenterline of the strip. This is indicated in FIG. 4.

Referring to FIG. 4, the axis 73 represents the axis of the former andalso the central axis of the film strip, the edges of which arerepresented by the dashed lines 78 and 78. The line 71 represents a foldline and the portion 88 after being folded with respect to the remainderof the sheet becomes a means of mounting and supporting part of theformer. There are two areas of the sheet, area 84 which is on the insideof a cutting line 75 which represents a convex parabola, with apex at77. The exterior part, around the outside of the parabola is identifiedby numeral 86. The part 86 is called the back portion of the folder andhas two wing tips 83 and 85. Once cut, the portion 84 is rolled into acylinder with two overlapping edges and is called the neck portion ofthe forming head. The length of the neck portion extends from point 77to the line 74.

A second parabola 75A is shown by dashed line which is a narrower curveand extends from the apex 77 to the line 74A. While it has not beenpossible, to date, to define a theoretical relationship in the form ofan exact equation of the parabola in reference to the angle between theback portion and the axis of the neck portion, and the thickness of thefilm, it has been determined by experiments and use, that for a film ofapproximately 0.008, and an angle of the order of 20 between the backportion and the axis of the neck portion that a parabola represented bythe equation y=: 2Dx, where D is the diameter of the formed plasticcylinder, provides very satisfactory operation of the former. Bychanging the equation of the parabola to provide a narrower, longer neckportion, or a wider, shorter neck portion, with a different acute angleof approach of the film over the back portion, equally satisfactoryoperations of the folder can be obtained. The lines 76 and 76 are drawnempirically, for convenience, and the triangular portions outside of thelines 76 and 76 are cut away. This provides less interference betweenthe folder and the film strip, and still gives sufiicient support to thelatter.

In constructing the former the sheet of material which, for example,might be a sheet of stainless steel of 0.010" thickness is laid out inaccordance with FIG. 4 with the proper parabola. The lines 76 and 76'are drawn and the two parts 84 and 86 are cut apart.

Referring now to FIGS. 5 and 7, FIG. 5 represents a support plate whichwill be described later. FIGS. 7A and 7B show how the inner portion ofthe parabola, part 84, is rolled into a circular cylindrical form withtwo overlapped edges 48 and 46. The designation 84A is given to therolled portion 84, which is now the neck portion of the former. Theleading edge over which the film is formed is the curve 75. The portion86 is shown in FIG. 7C with the part 88 bent along the line 71.

FIG. 7D shows how the rolled neck portion 84A is set on top of the backportion 86 with the corresponding points 77 placed together. The supportbracket 90 (of FIG. 5) is shown in position to hold the neck portion atthe proper position so that the angle a of FIG. 7E will be the correctvalue. An end view of FIG. 7D is shown in FIG. 7F. Following theassembly as shown by 7D the two wing portions 83 and are bent aroundinto the contour shown in 28A until the edges of the curve 75 of theback portion match along the edge 75 of the neck portion. The edges 75of the back and neck portions are then welded together and smoothed offto provide a proper sliding surface for the film over the forming edgeof the former.

A complete view of the former in its relationship to the arcuatepressure bar 44 and the pipe 42 for introducing the foaming materialinto the annulus, is shown in FIG. 6. The bracket is shown bolted bymeans 94 to the part 88 of the back portion. The neck portion 84A, theback portion 86A are shown, and the film strip 28 is shown progressingup along the contour of the back portion and over the forming edge ofthe former and issuing as a cylindrical plastic surface 35.

It has been found that the forming operation occurs at the edge 75, andwhen this is properly designed, either portion alone of the forminghead, that is part 84A, the neck portion, or 86A, the back portion, canbe used separately to form the plastic strip into a cylinder. In otherwords, if the neck portion 84A is used alone the film 28 is introducedat the correct angle a, the sheet will slide over the edge 75 and theentering film will form into a surface which would be identical withthat of the back portion. The film will then issue as a completecylinder. 'It is not necessary to 'have the back portion in positionunder this film 28A, except that it supports it, and prevents turbulentair, etc., from disturbing the smooth flow of the film. Thus, the twoportions of the forming head, that is, the neck portion 84A and the backportion 86A, need not be joined together. For example, the back can beused simply as a guide for the approaching film and the film then willbe given its proper forming by the contour of the edge 75 of the neckportion 84A. The edge 75 of the back portion can be spaced apart fromthe edge 75 of the neck portion and the two portions can be separatelysupported from the frame 18. In a similar manner, it is possible to usethe back portion above without the neck portion. In this case, when theback portion is properly designed and supported as a rigid unit, theedge 75 of the back portion will be the forming edge, or the edge oftransition, between the approaching film and the final formed cylinder.Thus, it is possible to use (1) the neck and back portions together,integrally connected, so that there is one continuous surface betweenthe two parts over which the film flows; or (2) the neck portion can beused alone; or (3) the back portion can be used alone; or (4) the neckportion and the back portion can be used together, but each spaced partfrom the other, with the back portion serving simply as a guide and theneck portion doing the forming and folding of the film.

While the material to be formed has been called a heat shrinkable film,there are many other materials that can be used. These include paper,plastics, such as vinyl plastics, including polyvinyl chloride,polyvinylidine chloride, vinyl chloride acetate, copolymers, andpolyolefins such as polyethylene and many others.

These plastics while being waterproof, flexible, and easily formablealso possess highly desirable dielectric properties. Accordingly, theseplastic films when used in accordance with the invention, not onlyprevent direct contact between the pipe and/or coating and ground, ormoisture, but also effectively insulate the pipe from stray electriccurrents.

Although these films are generally of a thickness equal to or less thanabout 0.010", this figure is not an absolute upper limit of the usablethickness. Generally the pipe size, coating thickness, formability ofthe film, and the type of film forming head will be one, all or some ofthe determining factors in deciding the upper limit of the usablethickness of a particular film. It is possible in some cases to increasethe usable thickness of a particular film beyond this upper limit bypreheating the film before forming or folding it about the pipe.

While the former can be made out of sheet material, or can be cast orotherwise fabricated it has been found experimentally that a sheetprovides a very good starting point for the construction of the formeras described above. Any suitable metal can be used. However, it has beenfound that the plastic film tends to carry an electric charge whichtends to attract dust and dirt particles and grit, which as they arecarried by the film over the forming surface cause it to Wear and erodeunless the material is of sufiicient hardness to prevent this. Thus, analuminum sheet will quickly wear, whereas a sheet of stainless steel, orhardened steel, would last a much longer time. Having fabricated theforming head out of sheet metal, it is, of course, possible also to usethe finished head as a pattern and to cast a corresponding former out ofhard metal such as steel.

FIGS. 2 and 3A illustrate the use of a longitudinal arcuate bar 44,which is positioned inside the formed plastic cylinder under theoverlapped edges, to act as a rigid surface against which the pressureroller 54 can press to provide a good seal between the gummed strip 52and the overlapped edges of the cylinder. FIG. 3B illustrates anembodiment in which the supply pipe 42 for the plastic material can beused as the back-up or support surface for the roller 54.

FIG. 8 illustrates an embodiment in which no pressure roller and back-upbar are used. Here a plurality of rollers 102A, 102B *102N are mountedin a frame 104 supported by the frame 18. The gummed strip 53 ispositioned between the rollers 102 and the overlapped seam. The pressureof the expanding foam between the central pipe 20 and rollers 102 causethe strip 53 to be tightly pressed against the plastic seam to providethe desired seal. Of course, a simple sliding surface can be used inplace of the rollers as a back-up plate against which the foam presses.

FIG. 9 shows a more detailed assembly of an operating embodiment of thisinvention. It is adapted for mill use. That is, it is adapted forstationary mounting on the floor of a shop and for the passage ofseparate lengths of pipe through the apparatus to be coated with foamand wrapped with film.

The apparatus is indicated generally by the numeral 110. This comprisesa rectangular first frame 112 with feet 144 which can be fastened to thefloor and appropriately leveled as necessary. There is a second frame116 which is mounted above the frame 112 and is supported by a pluralityof threaded rods 118 which are adapted to pass through the openings 120in the top of first frame 112. Inside the frame 112 near the top (andhidden from view) are a plurallity of sprocket driven nuts that areadapted to screw along the rods 118. The nuts are held in fixed positionso that as they are turned the rods 118 will move upward or downwarddepending upon the direction of rotation. The four nuts have sprocketsattached to them and a chain connects all four sprockets. Means areprovided including handle 124, as is well known in the art, to rotatethe nuts, all of which move in synchronism, so that the frame 116 willmove parallel to the frame 112 upward or downward in accordance with thedirection of rotation of crank handle 124. There are two tapered rollers126 and 128 journaled in bearings 130 in the top of the first frame 112and there are correspondingly a pair of rollers 127 and 129 which arejournaled in bearings 131 in the second frame 116. The two sets ofrollers are above each other, and by their shape they are adapted tohold securely a cylindrical object such as a long pipe. By making thesecond frame 116 movable with respect to the first frame 112, means areprovided to adapt the mechanism to handle pipes of different sizes, suchas from four inches to eighteen inches in diameter, for example. Thereare pulleys 138 and 140 on the rollers 126 and 128. These are driven bya belt 142 from pulley 136 on the output shaft of a gear reducer 134which is driven by motor 132. An idler 144 may be used in conjunctionwith the pulleys 136, 13-8 and 140. Thus the lower rollers are turned bythe power means. Since a pipe would be grasped tightly by the two pairsof rollers, the pipe will be moved through the apparatus in accordancewith the rotation of the pulley 136.

The roll of plastic film 156 is held in a third frame 146 which issupported on one corner post of the first frame 112 by means of the pins148 and 149 which fit into sockets 150 and 151. This arrangement permitsthe frame to be rotated in a horizontal plane by an angle of 90 so thatthe frame and the roll are out in a free operating area at the side ofthe frame 112. By this means third frames 146 of different sizes,suitable for rolls of different width, can be interchanged. Thus, forsmaller pipes, where a narrower film reel is needed, a shorter framewith a correspondingly shorter roll can be inserted. The third frame 146has a pair of bearings 152 which support a shaft 154 which carries theroll of plastic film 156 from which is unreeled, the sheet 158.

There is a horizontal arm 160 attached to the second frame 116. This armsupports a fourth frame 162 by means not shown but well understood inthe art. The frame 162 supports a horizontal idler roller 164 and thefolder 166 described in connection with FIGS. 4, 5, 6 and 7. When theframe 162 is in position attached to arm 160, the film strip 158 goesaround the idler roller 164 and over the folding edge and is formed intoa cylinder, coming out on the right side of the apparatus.

Also attached to the second frame 116 is the tube or pipe 172 throughwhich the plastic foam materials are injected into the annular space anda mandrel 174 comprising a strip of metal, as shown in FIGS. 1, 2 and 3,are mounted to the frame. There is also a roll 168 of adhesive coatedtape, which is supported on arm 170. The strip of tape unreeling fromthe roll 168 is pressed against the joint in the molded strip of plasticby means of the roller 176.

While the cylindrical objects that have been described above, assuitable for coating by the method of this invention, have been circularin cross section, it will be clear that the cylindrical object can be ofany desired cross section. Thus objects of square, rectangular, oval,cross section can be coated, the main difference being that thethickness of the coating will not be uniform over the entire surface.This system for applying coatings can be used with pipes, conduits,ducts, wave guides, cables and similar objects.

While the invention has been described with a certain degree ofparticularity it is manifest that many changes may be made in thedetails of construction and the arrangement of components. It isunderstood that the invention is not to be limited to the specificembodiments set forth herein by way of exemplifying the invention, butthe invention is to be limited only by the scope of the attached claimor claims, including the full range of equivalency to which each elementor step thereof is entitled.

For example, the folder has been described as a single, unitarycylindrical structure into which the cylindrical object to be coated isinserted. However, it is realized that in many instances, this devicemust be made to encircle a long continuous pipe, conduit or cable wherean end is not available. In such cases we contemplate that the folderdescribed can be constructed in two or more portions which are removablyfastened together, or hinged to each other, so that the folder can beopened to encircle the pipe and then locked in its cylindrical form.Consequently when we speak of a folder, we include a single rigidassembly, or an assembly of two or more parts which can be joined into asubstantially rigid assembly.

What is claimed is:

1. Apparatus .for simultaneously applying to an elongated cylindricalarticle a circumferential layer of a selected coating material and ameans for retaining said coating comprising:

(a) a support frame;

(b) means to axially move said article and said frame relatively to eachother;

(e) means, mounted on said frame, to supply a film strip in a directioncolinear with, and in synchronism with, the movement of said conduit;

(d) forming means supported by said frame and surrounding said articleto fold and overlap said film at the top so as to create downstreamabout said article a substantially unsupported cylindrical tubular formof selected diameter larger than said article;

(e) a pressure bar positioned interiorly of said overlapped film andextending downstream of said forming means;

(f) means to position a seal strip exteriorly upon said overlapped film;and

(g) means to inject said coating material into the annular space of saidcylindrical tubular form between said conduit and said film.

2. The apparatus as in claim 1 in which said film means comprises asynthetic heat shrinkable film.

3. The apparatus as in claim 1 in which said means to seal includesmeans to apply pressure to said strip against said pressure bar.

4. The apparatus as in claim 3 in which said means to apply pressurecomprises roller means on the strip and elongated longitudinal arcuatemeans inside the overlapped edges of said strip.

5. The apparatus as in claim 1 in which said pressure bar comprises asmall diameter conduit, said conduit being a part of said means toinject said coating material.

6. The apparatus as in claim 1 in which said pressure bar comprises anelongated mandrel curved to the radius of the inside of .said overlappededges of said formed strip.

7. The apparatus as in claim 1 in which said folding and wrapping meanscomprises a reversing folding means.

8. The apparatus as in claim 1 in which said coating material comprisesa foamed plastic material.

9. The apparatus of claim 8 in which said foam is chemically generatedwithin said annular space, and ineluding conduit means inside saidannular space through which the raw materials of said foam are supplied.

10. The apparatus as in claim 1 in which said means to supply said filmstrip comprises a roll of said film supported by said frame androtatable about an axis transverse to the axis of said article.

11. Apparatus of claim 1 in which said article is pipe.

12. Apparatus of claim 1 in which said article is an electrical cable.

13. Apparatus of claim 1 wherein said forming means comprises means forcontinuously forming a fiat strip of sheet material into a cylindricalform comprising:

(a) a cylindrical neck portion formed of a sheet of selected materialcut at one end in the convex form of a parabola with its axis colinearwith the axis of said sheet and of the strip to be formed, said sheetrolled into an approximate right circular cylinder with its axisparallel to the axis of said parabola, the parabolic cut end of saidsheet comprising the forming edge of said former means; and

(b) means to carry the strip to be formed at an acute angle to the axisof said neck portion toward said forming edge, the central axis of saidstrip aligned with the apex of said parabola, said strip passing oversaid forming edge and into and through said neck portion.

14. The folder means as in claim 13 including a leading supportingmeans, or back portion, comprising:

(a) the portion of said sheet outside said parabola with its wingportion bent in such a manner that when the axis of said back portion isat an acute angle to said neck portion the parabolic edge of said wingportions will conform to the forming edge of said neck portion.

15. The folder means as in claim 14 in which the parabolic edges of saidneck and back portions are joined, as by welding.

16. The folder means as in claim 14 in which the parabolic edges of saidneck and back portions are spaced apart.

17. The former means as in claim 16 including means to vary saidspacing.

18. Apparatus of claim 1 wherein said forming means comprises means forcontinuously forming a fiat strip of sheet material into a cylindricalform, comprising:

(a) a back portion formed of a sheet of selected material cut at one endin the form of a concave parabola with its axis colinear with the axisof the sheet and of the strip to be formed;

(b) said sheet formed by bending the two wing portions in a continuoussmooth surface until they approach each other surrounding and in contactwith a cylindrical mandrel of suitable diameter, the axis of said 55mandrel set at a selected acute angle to the plane of the back portion;

(c) means to permanently support said wing and back portions in thisshape, the parabolic edge comprising the forming edge; and

(d) means to carry the strip to be formed along and colinear with saidback portion, over said forming edge and through said wing portions inthe form of a cylinder.

19. Apparatus for simultaneously applying to an 65 elongated cylindricalarticle a circumferential layer of a selected coating material and ameans for retaining said coating comprising:

(a) a first support frame and means to fasten said first frame to ahorizontal surface;

(b) at least two parallel spaced first rollers mounted in hearings onthe top of said first frame; and motor means to rotate said rollers;

(0) second frame means supported on top of said first frame by aplurality of spaced vertical screw means \1 1 1 2 in operative relationto a corresponding plurality of (g) means to inject in the annular spacebetween said nuts, and means to rotate said nuts in synchronism objectand said formed cylindrical film the chemical so as to raise or lowersaid second frame with respect mammals equlred to form Sald coatlngtosaid first frame, at least two parallel spaced second rollers supportedin bearings in said second frame, 5 References cued whereby cylindricalobjects of different diameter can UNITED STATES PATENTS be held betweensaid first and second rollers and 3,434,502 3/1969 Smelling 138 13 3traversed horizontally therethrough; 3,432,582 3/ 1969 Bender 26447 (d)third frame means supported from said first frame 3,223,571 12/ 1965Straughan 15686 means, said third frame having bearings supporting a 103, 9,0 5 8/ 1968 Hy and, Jr 156195 horizontal shaft, which carries aroll of plastic film,

said shaft perpendicular to the axis of an object held FOREIGN PATENTSin said rollers; 965,185 7/1964 Great Britain 264-47 (e) fourth framemeans supported from said second 15 I frame and carrying an idler rollerparallel to the axis CHARLES VAN HORN Pnmary Exammer of said roll offilm, and supporting a folder for form- F. FRISENDA, JR., AssistantExaminer ing said film into a cylinder surrounding an object held insaid rollers and passing through said folder; (f) means to seal saidformed cylindrical film; and 20 15 3 391 392, 443, 475, 494, 499 545 57

